“We have got to make sure that these tapes, if they exist, don’t mysteriously disappear,” Sen. Mark Warner, D-Va., the top Democrat on the Senate Judiciary Committee, said on ABC’s “This Week With George Stephanopoulos” on Sunday. “So I have asked, others have asked, to make sure the tapes are preserved if they exist.”

“If they exist, Congress needs to get them,” Rep. Adam Schiff, D-Calif., said on CBS’ “Face the Nation.” “If they are not provided willingly, Congress should subpoena them. And if they’re not in existence — if this was another fabrication by the president — he needs to come clean about it.”

“If there are tapes, the president should turn them over immediately, of course,” Senate Minority Leader Chuck Schumer said on CNN’s “State of the Union.” “To destroy them would be a violation of law. But he should turn them over to Congress and to the investigators. If there are no tapes, he should apologize to both Jim Comey and the American people for misleading them.”

Those calls came two days after Trump seemed to threaten the ousted FBI director on Twitter.

James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press!

“I’ve talked to the president,” press secretary Sean Spicer told reporters at his daily briefing. “The president has nothing further to add on that.”

“Are there recording devices in the Oval Office or the presidential residence?” a reporter asked.

“There is nothing further to add on that,” Spicer replied.

The latest firestorm for Trump’s White House began Tuesday, when Comey, who had been overseeing the FBI’s investigation into whether the Trump campaign had ties to Russia, was unceremoniously fired by the president. In his letter to Comey, Trump claimed that the FBI director had informed him “on three separate occasions” that he was not under investigation by the FBI. Yet in an interview with NBC News’ Lester Holt on Thursday, Trump said that the investigation was on his mind when he decided to fire Comey.

“When I decided to just do it, I said to myself, I said, ‘You know, this Russia thing with Trump and Russia is a made-up story. It’s an excuse by the Democrats for having lost an election that they should’ve won,'” Trump said.

On Saturday, Trump told reporters on Air Force One that the White House was seeking to “make a fast decision” on a new FBI director and that a nominee could be announced by the end of this week. According to the New York Times, the White House conducted interviews with eight candidates — including acting FBI Director Andrew McCabe, Sen. John Cornyn, R-Texas; New York Appeals Court Judge Michael Garcia; and former Assistant Attorney General Alice Fisher — this weekend.